Disubstituted aminoethylcyclohexanones



Patented Oct. 13, 1953 'nrsunsrrrumno AMINOETHYECYGBO HEXANONES:

John A. Hogg, J erome Korman, William. Bradley Reid, Jr.,, and Alan H. Nathan, Kalamazoo Mich assigpors' to The Upjohn Company, Kalamazoo; a. corporation of Michigan'- No Dr mas. application February 24, 1951, senarNo. 212,672

9' Claims. 1

This invention relates to Z-(B-dlsubstituted aminoethyl); 4; -hydrocarbonoxycyclohexanones and, to amethodafor'thein productiom, Thisam plication is' a continuation-ing part: of: our a ppllicationz-SerialNo; 119;7l7!7',file d Qctober5; 1949.

The. compounds of the present, invention have; the general: structural formulae wherein, each R;- is: a: hydrocarbon radical cone taming? from; one ta even; carbon. atorna, incl n-- sive, such as the methyl, ethyl, propyli s nropyli, hutyl; isohutyl; pentyli, 1mm, heptx1-, cyclopropyl, yclobuiw s.v cyc1on nty1,.- cycl hexyla phenyland benzyl radicals.- and: the.- like. the compounds of, this invention; the; radicals? designated R, man be the same. on diflierent; hydrocarbon radicals; The group: RQ -is= herein: termed: a hy rocarbone 3! roup; and the: preferredembodiment of: It is methyl.

The products of this invention, when subjected to treatment with, Grignard reagents or) alkalimetal alkyls, give addition products which after hydrolysis, yield 1 alkyl 2 (p-disubst'ituted aminoethyl) 4 hydrocarbonoxycyclohexanols which-are more fully disclosed and claimed in our copending application- Serial 212,673; filed February 24-, 1951'.

Dehydration of the resulting I-alkyl-Z-(fi-disubstituted aminoethyl) -Lhydrocarbonoxycyclo hexanols produces I-alkyl 2' (*fi disubstituted aminoethyl) 4 hydrocarbonoxycyclohexenes which are more fully disclosed" and claimed in our copending application, Serial 212674, filed February-24, 1 95-1.

Addition of cyanogen bromide to the l-alk-yl- Z-(p-disubstitutedaminoethylr 4 hydrocarbonoxycyclohexenes described hereinbefore and decomposition of theresulting quaternary salt give 1' alkyl-Z-(B-bromoethyl) -4hydrocarborroxycycl'ohexenes which aremorefiill'y disclosed and claimed in: the copend-ingapplication of John A. Hogs, Seria1i212;67-5, filedlFebruary 243-1951 The compounds of: the present: invention can be prepared starting with a para-hydrocarbonoxyphcnol (for example, a. monoalky-l ether of hydroquinone) having; tl-ie-- formula:

wherein is a hydrocarbon radical as'indicated in the foregoing definition; of R. Such componnds rea ly react with three molecules, 01. 3X- drog ent, inthe. presence. of; a nickel; catalyst." t temperatures. between approximately 13 0"an'd approximately 30.0 degrees centigradev to yield the corresponding saturated; compound;v a nara-hyd1ocanbonoxycyclohexanolf having, the,v formula I which can ne. oxidized to, a pararhydrocarbonoxy cvclohexanonehavins the formula which is readily converted by means of heat and powdered soft glass into a 2-carbethoxy-4-hydrocarbonoxycycloh'exanone having the formula:

Hr wherein R has the significance hereinbeiore" assigned.

The resulting 2-carbethoxy-4-hydrocarb'onoxycyclohexanone is then condensed in the presence or sodium or potassium withahalogen-substrtuted tertiary amine having: the" formula:

wherein X is a halogen, e.-, g (511101 111650? brom ne, and each R is a hydrocarbon radical having the significance hereinbiefore assigned.v ,3 -D iethyl-,- aminoothy-l chloride is. a typical example of such amine. Ordinarily the reaction is conducted in an inert organic solvent, such as benzene, toluene or xylene, at a temperature between approximately 80 and approximately 140 degrees centigrade, and preferably at about the refiux temperature of the solvent employed. The reaction is complete in from to 20 hours, at the end of which time, the product, a 2-carbethoxy-2- (p disubstituted aminoethyl) 4 hydrocarbonoxycyclohexanone having the formula: HI H10 c=o RO-H J-CHzCHz-NR:

wherein the Rs have the significance hereinbefore specified, may be isolated in conventional manner, such as by extraction from the organic layer with dilute acid, e. g., hydrochloric or sulfuric, and subsequent neutralization with alkali, e. g., potassium carbonate or sodium hydroxide. The crude product is then extracted with a solvent such as ether or benzene and isolated by evaporation of the solvent.

The 2-carbethoxy-2-(fl-disubstituted aminoethyl) 4 hydrocarbonoxycyclohexanone thus produced is then decarbalkoxylated, as with hydrochloric or sulfuric acid having a concentration between approximately 10 and approximately 20 percent by weight at a temperature between approximately 80 and approximately 110 degrees centigrade, preferably at about reflux temperature, for a period of between approximately 10 and approximately with barium hydroxide in alcohol, to produce a 2 (p disubstituted aminoethyl) 4 hydrocarbonoxycyclohexanone having the formula:

ii. wherein the R's have the hereinbefore assigned significance. After decarbalkoxylation, the product is isolated in conventional manner, as by treatment with alkali, extraction with ether, and distillation.

The following examples illustrate typical compounds of the invention and the methods by which they can be prepared. It will be understood that changes and modifications may be introduced by those skilled in the art, without departing from the spirit or scope of the invention.

PREPARATION 1.4-1\ns'rHoxYoYcLoHExANoL AND OTHER 4-ALKOXYCYCLOHEXANOLS A solution of 500 grams of 4-methoxyphenol (monomethyl ether of hydroquinone) in 800 milliliters of ethanol was subjected to hydrogenation in the presence or 165 grams (wet weight) of a Raney nickel catalyst prepared by the method of Adkins and Pavlic [J Am. Chem. Soc., 68, 147 (1946)]. The initial pressure of the hydrogenation at room temperature was between approximately 1000 and approximately 1800 pounds per square inch and the final temperature was about 140 degrees centigrade. The total time required for the hydrogenation was approximately 2 to 3 hours. After removal or the catalyst and solvent, distillation of the residue gave 445 grams (85 percent) of 4-meth- 20 hours, or, alternatively,

(J'- oxycyclohexanol as a colorless liquid boiling at 104-105 degrees centigrade at a pressure of 13 millimeters of mercury.

In a like manner, 4-ethoxycyclohexanol can be obtained by the hydrogenation of 4-ethoxyphenol (ethyl ether of hydroquinone); 4-propoxycyclohexanol can be obtained from 4-propoxyphenol; 4-n-butoxycyclohexanol can be obtained from 4-n-butoxyphenol; and 4-benzyloxycyclohexanol can be obtained from 4-benzyloxyphenol. The 4-alkoxyphenols (ethers of hydroquinone) can be prepared by the method described by Klarmann, Gatyas and Shternov in J. Am. Chem. Soc., 54, 298 (1932).

PREPARATION 2.4-METH0XY0Y0L0HEXAN0NE AND OTHER 4-ALKOXYCYCLOHEXANONES The oxidation of 4-methoxycyclohexanol (Preparation 1) was carried out according to the procedure of Helfer [Helv. Chim. Acta, '7. 953 (1924)]. To a solution of grams of potassium dichromate in grams of sulfuric acid and 400 milliliters of water cooled in an ice-bath was added with vigorous stirring 58.5 grams or 4-methoxycyclohexanol. The temperature of the reaction mixture rose rapidly to '70 degrees centigrade, and the color became brown. Stirring was continued until the temperature decreased, after which the product was extracted with ether, isolated by removal of the ether and purified by distillation; it boiled at '12 degrees centigrade at a pressure of 9 millimeters of mercury.

In a like manner, 4-ethoxycyclohexanone can be obtained by the oxidation of 4-ethoxycyclohexanol; 4-propoxycyclohexanone can be obtained from 4-propoxycyclohexanoi; 4-n-butoxycyclohexanone can be obtained from 4-nbutoxycyclohexanol; and 4-benzyloxycyclohexanone can be obtained from 4-benzyloxycyclohexanol.

PREPARATION 3.-2 cAxBE'rHoxY 4 METHOXYCYCLO- HEXANONE AND OTHER 2-CARBETHOXY-4-ALKOXY- CYCLOHEXANONES The preparation of this compound was carried out by the method heretofore described for the preparation of 2-carbethoxycyclohexanone (Snyder, Brooks and Shapiro, Org. Syntheses, Coll. Vol. II, John Wiley and Sons, New York, 1943, p. 531; Cf. Cook and Laurence, J. Chem. Soc., 1938, 58). To a solution of 46 grams (2 moles) of sodium in 600 milliliters of absolute ethanol in an ice-salt bath was added at 10 degrees centigrade with vigorous stirring a cold solution of 256 grams (2 moles) of 4-methoxycyclohexanone (Preparation 2) in 292 grams (2 moles) of ethyl oxalate during a period of 15 to 20 minutes. The mixture was stirred at ice-bath temperature for about 1 hour and at room temperature for about 6 hours, acidified with ice-cold sulfuric acid, and extracted with benzene. After removal of the henzene on a steam-bath, about 25 grams of powdered soft glass was added to the residual 2- ethoxalyl-4-methoxy-cyclohexanone and the mixture was heated to degrees centigrade with stirring at a subatmospheric pressure of approximately 50 millimeters of mercury until the evolution of carbon monoxide had ceased. Distillation of the residue gave 132.4 grams (33 percent) of 2-carbethoxy-4-methoxycyclohexanone as a heavy yellow oil which boiled at 100-105 degrees centigrade at a pressure of 1.2 millimeters of mercury.

In a like manner, 2-carbethoxy-4-ethoxycyclohexanone can be obtained by the ethoxalylation of 4-ethoxycyclohexanone followed by decarbonylation of the 2-ethoxalyl-4-ethoxycyclohexanone; 2 carbethoxy 4 propoxycyclohexanone can be obtained from 4-propoxycyclohexanone; 2-carbethcxy-4-n-butoxycyclohexanone can be obtained from 4-n-butoxycyclohexanone; and 2- carbethoxy-4-benzyloxycyclohexanone can be obtained from 4-benzyloxycyclohexanone.

PREPARATION 4.-2-cAn:BErHoxY-2- B-DIETHYLAMINO- ETHYL) 4 METHOXYOYCLOHEXANONE AND OTHER 2-CARBETHOXY 2- (B-DIETHYLAMINQETHYL)-4-AL- KOXYOYCLOHEXANONES To a suspension of 2.3 grams (0.1 mole) of sodium sand in 200 milliliters of anhydrous toluene was added dropwise with stirring a solution of 20.0 grams (0.1 mole) of Z-carbethoxyl-methoxycyclohexanone (Preparation 3) in 25 milliliters of anhydrous toluene. After the addition, the mixture was heated under reflux with stirring for 3 hours, and then stirred overnight at room temperature. The suspension of the sodio derivative was again heated to boiling and to it was added dropwise, with stirring during 3 hours, a solution of 13.6 grams (0.1 mole) of fl-diethylaminoethyl chloride in 25 milliliters of anhydrous toluene. After heating under reflux for an additional 7 hours, the mixture was cooled and extracted with dilute hydrochloric acid. The acid extract was neutralized with sodium hydroxide solution, saturated with solid potassium carbonate and extracted with ether. I'he ether extracts were washed with water and dried, and the ether was evaporated. Distillation of the residue gave a 67 percent yield of 2-carbethoxy-2-(fi diethylaminoethyl) 4 methoxycyclohexanone as a nearly colorless liquid which boiled at 132-135 degrees centigrade at a pressure of 0.15 millimeter of mercury; n =1.4715.

In a like manner, 2-carbethoxy-2-(.fi-di-n-butylaminoethyl) 4 benzyloxycyclohexanone can be obtained by the alkylation of 2-carbethoxy-4- benzyloxycyclohexanone with di-n-butylaminoethyl chloride, which can be prepared according to the procedures of Barnett et al. [J Am. Chem. Soc, 59, 2248 (1937)], and Blicke and Maxwell [ibid., 64, 428 (1942)]; and Z-carbethoxy 2 (fi-dibenzylaminoethyl)-4-n-butoxycyclohexanone can be obtained b the alkylation of 2-carbethoxy-4n-butoxycyclohexanone with dibenzylaminoethyl chloride which can be prepared according to the procedure of Dupre et al. (J. Chem. 600., 1949, 500).

Example 1.-2-(fl-diethylaminoethyl) -4methoccycycloltexanone A solution of 17.0 grams (0.05 mole) of 2-carbethoxy 2- (fl-diethylaminoethyl) -4-methoxycyclohexanone (Preparation 4) in 250 milliliters of 20 percent sulfuric acid was heated under reflux for 18 hours. After cooling, the solution was neutralized with'sodium hydroxide, saturated with solid potassium carbonate and extracted with ether. The ether extracts were washed with water and dried, and the ether was evaporated. Distillation of the residue gave a 76 percent yield of 2- (.fl-diethylaminoethyl) -4-methoxycyclohexanone as a colorless oil which boiled at 112-114 degrees centigrade at a pressure of 0.8 millimeter of mercury; n =1.4680. The product formed a crystalline salt with oxalic acid which melted at 111-112 degrees centigrade.

Analysis (oxalate) .Calcu1ated for C15H2'106NI C, 56.76; H, 8.58; N, 4.41. Found: C, 56.89; H, 8.58; N, 4.36.

Other examples In a manner similar to that described in Example 1, 2-(B-di-n-butylaminoethyl)-4-benzyloxycyclohexanone can be obtained from 2-carbethoxy 2-(B-di-n-butylaminoethyl) 4-benzyloxycyclohexanone; and Z-(fl-dibenzylaminoethyl)-4-n-butoxycyclohexanone can be obtained from 2-carbethoxy-2- (A-dibenzylaminoethyl) -4- n-butoxycyclohexanone.

We claim:

1. A 2 (,B-aminoethyl)-4-hydrocarbonoxycyclohexanone having the formula:

No references cited. 

1. A 2 - (B-AMINOETHYL)-4-HYDROCARBONOXYCYCCLOHEXANONE HAVING THE FORMULA: 